feat(acap-logging): Make env_logger optional and remove syslog (#185)

AP Ljungquist · web-flow · commit ac2cb60a7c82 · 2025-05-02T22:30:43.000+02:00
The reason is to make the cost in terms of storage smaller because this
is a utility that most applications would use and the cost adds up if
many applications are installed at the same time.

Using the app profile, the size of hello_world is:
- 387K (before)
- 323K (after, with default features. `size` total is 323,436)
- 323K (after, without default features. `size` total is 286,169)

For reference the size of a no-op application compiled with the same
settings is 263K. These are all numbers for aarch64-unknown-linux-gnu.

Why the size as reported by `du` and `wc` does not decrease when I
expect it to is a mystery to me, but it's not a rabbit hole I want to
explore further at this time.

One bonus benefit of this change is that the device information will
no longer be duplicated in the syslog.
I.e. it will say:

&gt; May 02 17:17:38 abc hello_world[20894]: Logging initialized

instead of:

&gt; May 02 17:17:38 abc hello_world[20894]: abc hello_world[20894]: Logging initialized


---

`apps/*/Cargo.toml`:
- Enable `acap-logging/default` features to maintain the ability to
  run the apps interactively.
- Propagate the `acap-logging/default` feature to make it possible to
  compile `hello_world` with tty support, as one would during
  development, and without it, as one would when deploying the app to 
  production. This serves to document one way in which this can be
  achieved and also to make it easier to test that it works as expected
  (see `docs/manual-tests.md`).

`apps/reverse_proxy/Cargo.toml`,
`crates/axparameter/Cargo.toml`:
- Remove `syslog` and `log` because they were not used and `syslog`
  should not be used.

`crates/acap-logging/Cargo.toml`:
- Bump the version to make these improvement instantly releasable
  because they are meaningful and it is unclear when the next
  improvements to the crate would be made.

`docs/manual-tests.md`:
- Added to start documenting some of the use cases that the apps and
  tools have been designed for because it can be difficult to remember
  and new contributors don't even have the chance to remember. I view
  this as an experiment and may change the approach to documentation or
  go back to relying on git logs.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -24,6 +24,7 @@ glib = "0.20.9"
 glib-sys = "0.20.9"
 glob = "0.3.1"
 libc = "0.2.153"
+libsyslog = "0.1.1"
 log = "0.4.22"
 pkg-config = "0.3.30"
 regex = "1.7.2"
@@ -32,7 +33,6 @@ reqwest-websocket = "0.4.1"
 semver = "1.0.23"
 serde = "1.0.204"
 serde_json = "1.0.120"
-syslog = "6.1.1"
 tar = "0.4.40"
 tempdir = "0.3.7"
 tempfile = "3.10.1"
@@ -44,7 +44,7 @@ tracing-subscriber = "0.3.18"
 url = "2.5.2"
 
 acap-build = { path = "crates/acap-build" }
-acap-logging = { path = "crates/acap-logging" }
+acap-logging = { path = "crates/acap-logging", default-features = false }
 acap-ssh-utils = { path = "crates/acap-ssh-utils" }
 acap-vapix = { path = "crates/acap-vapix" }
 axevent = { path = "crates/axevent" }
diff --git a/apps-aarch64.checksum b/apps-aarch64.checksum
@@ -1,14 +1,14 @@
 2307f06b6728658c1e0d6d9251e3fbd22f209b9d  target-aarch64/acap/Challenge_Build_Tools_1_0_0_all.eap
-af60683f2d875b37e6ff8e4bbb28c78b21b05013  target-aarch64/acap/axparameter_example_0_0_0_aarch64.eap
-650b6a80dc4ebba5cbaec7fb9e38135cd4c82bfa  target-aarch64/acap/axstorage_example_0_0_0_aarch64.eap
-0af03d5bec50d42ec579cb07360dad4e25c413ea  target-aarch64/acap/bounding_box_example_0_0_0_aarch64.eap
-911a4cbf2cc7a67590488195bfdd87fb205ce73c  target-aarch64/acap/consume_analytics_metadata_0_0_0_aarch64.eap
+db7ab42f035a7eae0b5a82eb7ec9cc5d0584a8cc  target-aarch64/acap/axparameter_example_0_0_0_aarch64.eap
+bd570bf0158fddfd9bc741099c87a1a14ffe788f  target-aarch64/acap/axstorage_example_0_0_0_aarch64.eap
+dd15c890a3fb8fb38c5ce2e8364f215ff1eb8610  target-aarch64/acap/bounding_box_example_0_0_0_aarch64.eap
+dfd925c003c30164c00dfc51676b6e1317a0fa6d  target-aarch64/acap/consume_analytics_metadata_0_0_0_aarch64.eap
 16310c12bb50db85d69c744d13c93ebf0c628953  target-aarch64/acap/embedded_web_page_0_0_0_aarch64.eap
-46e8c7814f066c076a2d7a05f044548670672d4e  target-aarch64/acap/event_subscribe_1_0_0_aarch64.eap
-f79353594a90130cec6226583fff68e56fd5c1ec  target-aarch64/acap/hello_world_0_0_0_aarch64.eap
-6c96005d12ca0077de6c82aeb20cfe1e915e6a0e  target-aarch64/acap/inspect_env_0_0_0_aarch64.eap
-ac57232da6402933012e506ac9dc08d94a5fe90b  target-aarch64/acap/licensekey_handler_0_0_0_aarch64.eap
-0db9eaa42746e94de7ccfcd5a0fc078da6fe1412  target-aarch64/acap/reverse_proxy_0_0_0_aarch64.eap
-e5a389a499727973ccd401b4c16f5eddd928cb02  target-aarch64/acap/send_event_1_0_0_aarch64.eap
+148ad07bd1c5d213ae055c0f7050de454d6cb939  target-aarch64/acap/event_subscribe_1_0_0_aarch64.eap
+5712d955c8ea45a774597a6032a16af72a24e118  target-aarch64/acap/hello_world_0_0_0_aarch64.eap
+222f821339cf36e88596d85427740de3536573bf  target-aarch64/acap/inspect_env_0_0_0_aarch64.eap
+74d6106b8f0afe7e3342ae3b470d8b81e7aa5150  target-aarch64/acap/licensekey_handler_0_0_0_aarch64.eap
+5dc0969dcbe6ca09aabcef9530a0f77786932b22  target-aarch64/acap/reverse_proxy_0_0_0_aarch64.eap
+c94b3ba49a3897617dc13599ffbc0642681133e5  target-aarch64/acap/send_event_1_0_0_aarch64.eap
 9df8dead66b245aa19d3aafa758871118b8cc25f  target-aarch64/acap/using_a_build_script_0_0_0_aarch64.eap
-35971d17919db34bb275057fef80b0e8cd13484f  target-aarch64/acap/vapix_access_0_0_0_aarch64.eap
+e1edf29b82e9c04c044309f63571e8898fcfe1f6  target-aarch64/acap/vapix_access_0_0_0_aarch64.eap
diff --git a/apps-aarch64.filesize b/apps-aarch64.filesize
@@ -1,14 +1,14 @@
 899	target-aarch64/acap/Challenge_Build_Tools_1_0_0_all.eap
-3414	target-aarch64/acap/axparameter_example_0_0_0_aarch64.eap
-3484	target-aarch64/acap/axstorage_example_0_0_0_aarch64.eap
-2132	target-aarch64/acap/bounding_box_example_0_0_0_aarch64.eap
-2020	target-aarch64/acap/consume_analytics_metadata_0_0_0_aarch64.eap
+2862	target-aarch64/acap/axparameter_example_0_0_0_aarch64.eap
+2937	target-aarch64/acap/axstorage_example_0_0_0_aarch64.eap
+1598	target-aarch64/acap/bounding_box_example_0_0_0_aarch64.eap
+1480	target-aarch64/acap/consume_analytics_metadata_0_0_0_aarch64.eap
 899	target-aarch64/acap/embedded_web_page_0_0_0_aarch64.eap
-4077	target-aarch64/acap/event_subscribe_1_0_0_aarch64.eap
-1948	target-aarch64/acap/hello_world_0_0_0_aarch64.eap
-1982	target-aarch64/acap/inspect_env_0_0_0_aarch64.eap
-1970	target-aarch64/acap/licensekey_handler_0_0_0_aarch64.eap
-10911	target-aarch64/acap/reverse_proxy_0_0_0_aarch64.eap
-3982	target-aarch64/acap/send_event_1_0_0_aarch64.eap
+3525	target-aarch64/acap/event_subscribe_1_0_0_aarch64.eap
+1406	target-aarch64/acap/hello_world_0_0_0_aarch64.eap
+1441	target-aarch64/acap/inspect_env_0_0_0_aarch64.eap
+1430	target-aarch64/acap/licensekey_handler_0_0_0_aarch64.eap
+10362	target-aarch64/acap/reverse_proxy_0_0_0_aarch64.eap
+3430	target-aarch64/acap/send_event_1_0_0_aarch64.eap
 899	target-aarch64/acap/using_a_build_script_0_0_0_aarch64.eap
-11914	target-aarch64/acap/vapix_access_0_0_0_aarch64.eap
+11379	target-aarch64/acap/vapix_access_0_0_0_aarch64.eap
diff --git a/apps/axparameter_example/Cargo.toml b/apps/axparameter_example/Cargo.toml
@@ -10,3 +10,6 @@ log = { workspace = true }
 
 acap-logging = { workspace = true }
 axparameter = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/axstorage_example/Cargo.toml b/apps/axstorage_example/Cargo.toml
@@ -12,3 +12,6 @@ log = { workspace = true }
 acap-logging = { workspace = true }
 axstorage = { workspace = true }
 libc = "0.2.158"
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/bounding_box_example/Cargo.toml b/apps/bounding_box_example/Cargo.toml
@@ -10,3 +10,6 @@ log = { workspace = true }
 
 acap-logging = { workspace = true }
 bbox = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/consume_analytics_metadata/Cargo.toml b/apps/consume_analytics_metadata/Cargo.toml
@@ -10,3 +10,6 @@ log = { workspace = true }
 
 acap-logging = { workspace = true }
 mdb = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/event_subscribe/Cargo.toml b/apps/event_subscribe/Cargo.toml
@@ -12,3 +12,6 @@ log = { workspace = true }
 acap-logging = { workspace = true }
 axevent = { workspace = true, features=["async"] }
 futures-lite = "2.6.0"
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/hello_world/Cargo.toml b/apps/hello_world/Cargo.toml
@@ -8,3 +8,6 @@ publish = false
 log = { workspace = true }
 
 acap-logging = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/inspect_env/Cargo.toml b/apps/inspect_env/Cargo.toml
@@ -8,3 +8,6 @@ publish = false
 log = { workspace = true }
 
 acap-logging = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/licensekey_handler/Cargo.toml b/apps/licensekey_handler/Cargo.toml
@@ -9,3 +9,6 @@ log = { workspace = true }
 
 acap-logging = { workspace = true }
 licensekey = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/reverse_proxy/Cargo.toml b/apps/reverse_proxy/Cargo.toml
@@ -7,11 +7,12 @@ publish = false
 [dependencies]
 axum = { workspace = true, features = ["tokio", "ws"] }
 log = { workspace = true }
-env_logger = { workspace = true }
 futures = { workspace = true }
-syslog = { workspace = true }
 tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
 tower-http = { workspace = true, features = ["fs", "trace"] }
 serde = { workspace = true, features = ["derive"] }
 
 acap-logging = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/send_event/Cargo.toml b/apps/send_event/Cargo.toml
@@ -11,3 +11,6 @@ log = { workspace = true }
 
 acap-logging = { workspace = true }
 axevent = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/apps/vapix_access/Cargo.toml b/apps/vapix_access/Cargo.toml
@@ -13,3 +13,6 @@ url = { workspace = true }
 
 acap-logging = { workspace = true }
 acap-vapix = { workspace = true }
+
+[features]
+default = ["acap-logging/default"]
diff --git a/crates/acap-logging/Cargo.toml b/crates/acap-logging/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "acap-logging"
-version = "0.1.0"
+version = "0.1.1"
 edition.workspace = true
 description = "Logging utilities for ACAP applications"
 license = "MIT"
@@ -9,9 +9,10 @@ homepage = "https://github.com/AxisCommunications/acap-rs"
 repository = "https://github.com/AxisCommunications/acap-rs"
 
 [dependencies]
+env_logger = { workspace = true, optional = true }
+libsyslog = { workspace = true }
 log = { workspace = true }
-env_logger = { workspace = true }
-syslog = { workspace = true }
 
 [features]
-default = ["env_logger/auto-color"]
+default = ["tty"]
+tty = ["env_logger/auto-color"]
diff --git a/crates/acap-logging/src/lib.rs b/crates/acap-logging/src/lib.rs
@@ -1,15 +1,17 @@
 #![forbid(unsafe_code)]
 #![allow(clippy::needless_doctest_main)]
 #![doc = include_str!("../README.md")]
+#[cfg(feature = "tty")]
 use std::{env, io::IsTerminal};
 
 use log::debug;
 
 fn init_syslog() {
-    let formatter = syslog::Formatter3164::default();
-    let logger = syslog::unix(formatter).unwrap();
-    log::set_boxed_logger(Box::new(syslog::BasicLogger::new(logger))).unwrap();
-    log::set_max_level(log::LevelFilter::Debug);
+    libsyslog::Syslog::builder()
+        .level(log::LevelFilter::Debug)
+        .build()
+        .init()
+        .unwrap();
 }
 
 /// Set up app-logging as appropriate for the environment, then run the provided function.
@@ -25,14 +27,17 @@ fn init_syslog() {
 pub fn init_logger() {
     // Using `su -pc "..."` just says the "Connection to ... closed", and
     // I have not found another way to run as the SDK user over ssh and allocate a tty, so
-    // if we detect an `env_logger` configuration we write to stderr anyway.
+    // if we detect an `env_logger` configuration, we write to stderr anyway.
+    #[cfg(feature = "tty")]
     if std::io::stdout().is_terminal()
         || env::var_os("RUST_LOG").is_some()
         || env::var_os("RUST_LOG_STYLE").is_some()
     {
         env_logger::init();
-    } else {
-        init_syslog();
+        debug!("Logging initialized");
+        return;
     }
+
+    init_syslog();
     debug!("Logging initialized");
 }
diff --git a/crates/axparameter/Cargo.toml b/crates/axparameter/Cargo.toml
@@ -8,9 +8,3 @@ license = "MIT"
 glib = { workspace = true }
 glib-sys = { workspace = true }
 axparameter-sys = { workspace = true }
-
-[dev-dependencies]
-log = { workspace = true }
-syslog = { workspace = true }
-
-
diff --git a/docs/manual-tests.md b/docs/manual-tests.md
@@ -0,0 +1,34 @@
+This is not an exhaustive list, but the use cases listed here should work.
+
+
+## Run Hello World
+
+Note that this only works on AxisOS <12 as of writing.
+As a workaround the `run` command can be replaced by SSHing into the device and running the binary manually:
+
+```console
+$ RUST_LOG=debug /usr/local/packages/hello_world/hello_world
+```
+
+```console
+$ cargo-acap-sdk install -- -p hello_world
+$ cargo-acap-sdk run -- -p hello_world
+```
+
+All records except "Hello trace!" should be emitted and appropriately colored.
+
+## Start Hello World without default features
+
+On the device:
+```console
+$ journalctl -f
+```
+
+```console
+$ cargo-acap-sdk install -- -p hello_world
+$ cargo-acap-sdk run -- -p hello_world
+```
+
+All records except "Hello trace!" should be emitted and appropriately colored in the output on the device.
+
+The size of the executable should be noticably smaller than the one with default features.
